There are many food processes which can benefit from the use of a filter for purifying, clarifying, improving, and reclaiming edible liquids. The present invention is applicable to all such processes, such as reclaiming cooking oil in restaurants, and clarifying and improving the taste of wine.
Prior to the present invention, many restaurants have periodically passed the cooking oil used for deep fat frying through a porous pad in order to remove food particles. Such filtering, however, did not prevent the build-up of oil degradation products, like fatty acids, polymers, non-volatiles, volatiles and coloring bodies which adversely affect the taste and color of foods fried in such oil. Various efforts have been made to remove such acids and bodies from used cooking oil. U.S. Pat. No. 4,330,565 entitled "FRYER OIL TREATMENT COMPOSITION AND METHOD" issued to Friedman on May 18, 1982, discloses use of a composition of water, a food compatible acid, such as citric acid, tartaric acid, acetic acid, phosphoric acid or malic acid, and a carrier containing rhyolite or perlite. The carrier of Friedman may also contain in addition to the rhyolite or perlite; activated carbon, fuller's earth, silica gel, bauxite, alumina, and diatomaceous earth. U.S. Pat. No. 4,112,129 of Duensing et al entitled "COOKING OIL TREATING SYSTEM AND COMPOSITION THEREFOR" dated Sept. 5, 1978, discloses a filter composition for the same purpose of diatomite, synthetic calcium silicate hydrate, and synthetic magnesium silicate hydrate. In these processes and the process of copending U.S. Pat. No. 4,764,384, of John Gyann filed Apr. 3, 1986, entitled FILTERING MEDIA AND METHOD OF USING SAME, under common assignment with the present application, granulated filtering material is added to hot cooking oil to absorb unwanted taste constituents therefrom, and thereafter the filtering media is mechanically filtered from the cooking oil, thereby rejuvenating the cooking oil. In the practice of such processes, the cooking oil is generally filtered through a layer of filter paper to remove solid particles of food which may be present in the cooking oil and to remove the filter media itself. A filtering aid is generally employed with the filtering media to facilitate the flow of the cooking oil through the media to the paper filter.
Not all fast food restaurants utilize mechanical filter equipment to remove particles of food from the deep fat cooking oil. The processes disclosed above cannot be used in such fast food restaurants or require the addition of mechanical filtering equipment. It is an object of the present invention to provide a process for removing unwanted taste constituents from a liquid which does not require mechanical filtration equipment.
In some fast food restaurants, filtering of the filter media from the cooking oil by a mechanical filter fails to remove all of the filter media. As a result, the cooking oil becomes contaminated by filter media, and the filter media represents an undesirable additive to the rejuvenated cooking oil. Faulty mechanical filtering equipment can result in this condition of the rejuvenated cooking oil. It is a further object of the present invention to provide a process for filtering edible liquids which significantly reduces the possibility of contamination of the edible liquid by the filter media.
The filter media disclosed in U.S. Pat. No. 4,764,384 of John Gyann referred to above utilizes hydrated synthetic amorphous silica and synthetic amorphous magnesium silicate as its principal active agents, but a filter media limited to these active agents results in a slow mechanical filtration process. To increase the speed of filtration, a filtering aid is utilized, and the filter media disclosed in said patent application is diatomaceous earth, diatomaceous earth being selected because it also contributes to filtration. As a result, more filter media must be admixed with the cooking oil to produce satisfactory removal of unwanted taste constituents.
Duensing U.S. Pat. No. 4,112,129 seeks to create adequate flow rates in a filter medium of diatomite, synthetic calcium silicate hydrate, and synthetic magnesium silicate hydrate by control of particle size, but the particle size requirement makes it necessary to use more coarse materials than are conventionally available. It is an object of the present invention to eliminate or reduce the need for a filter aid, or to select materials of unconventional particle size, in the filter media utilized to remove unwanted taste constituents from an edible liquid.
The inventor has found that it is desirable to add some ingredient to the edible liquid, such as an antioxidant, which will remain in the liquid after treatment. It is a further object of the present invention to add ingredients to the edible liquid simultaneously with the filtration process.
It is a further objection of the present invention to provide an improved filtering media for use with edible liquids, particularly such a filtering media which is particularly suited for use in packets according to the present invention.